[PATCH] D140580: [SLP]Do not emit many extractelements, reuse the single one emitted.

Fri Feb 24 16:44:46 PST 2023

ABataev added a comment.

In D140580#4151643 <https://reviews.llvm.org/D140580#4151643>, @DaniilSuchkov wrote:

> This patch is causing a crash even after the 26fec4e845a833214d2b0036ea90f1b1c2418d50 <https://reviews.llvm.org/rG26fec4e845a833214d2b0036ea90f1b1c2418d50>
> IR:
>
>   target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:128-n8:16:32:64-S128-ni:1-p2:32:8:8:32-ni:2"
>   target triple = "x86_64-unknown-linux-gnu"
>   
>   define void @foo() #0 {
>   bb:
>     br label %bb1
>   
>   bb1:                                              ; preds = %bb1, %bb
>     %inst = phi i32 [ poison, %bb ], [ %inst58, %bb1 ]
>     %inst2 = getelementptr inbounds i32, ptr addrspace(1) poison, i64 poison
>     %inst3 = load i32, ptr addrspace(1) %inst2, align 4
>     %inst4 = add i32 %inst3, -1
>     store i32 %inst4, ptr addrspace(1) %inst2, align 4
>     %inst5 = add i32 poison, -1
>     %inst6 = mul i32 %inst4, %inst
>     %inst7 = mul i32 %inst6, %inst5
>     %inst8 = add nuw nsw i64 poison, 1
>     %inst9 = getelementptr inbounds i32, ptr addrspace(1) poison, i64 %inst8
>     %inst10 = load i32, ptr addrspace(1) %inst9, align 4
>     %inst11 = add i32 %inst10, -1
>     store i32 %inst11, ptr addrspace(1) %inst9, align 4
>     %inst12 = add i32 poison, -1
>     %inst13 = mul i32 %inst11, %inst7
>     %inst14 = mul i32 %inst13, %inst12
>     %inst15 = getelementptr inbounds i32, ptr addrspace(1) poison, i64 poison
>     %inst16 = load i32, ptr addrspace(1) %inst15, align 4
>     %inst17 = add i32 %inst16, -1
>     store i32 %inst17, ptr addrspace(1) %inst15, align 4
>     %inst18 = add i32 poison, -1
>     %inst19 = mul i32 %inst17, %inst14
>     %inst20 = mul i32 %inst19, %inst18
>     %inst21 = add nuw nsw i64 poison, 1
>     %inst22 = getelementptr inbounds i32, ptr addrspace(1) poison, i64 %inst21
>     %inst23 = load i32, ptr addrspace(1) %inst22, align 4
>     %inst24 = add i32 %inst23, -1
>     store i32 %inst24, ptr addrspace(1) %inst22, align 4
>     %inst25 = add i32 poison, -1
>     %inst26 = mul i32 %inst24, %inst20
>     %inst27 = mul i32 %inst26, %inst25
>     %inst28 = getelementptr inbounds i32, ptr addrspace(1) poison, i64 poison
>     %inst29 = load i32, ptr addrspace(1) %inst28, align 4
>     %inst30 = add i32 %inst29, -1
>     store i32 %inst30, ptr addrspace(1) %inst28, align 4
>     %inst31 = mul i32 %inst30, 47961
>     %inst32 = add i32 %inst31, -1
>     %inst33 = mul i32 %inst30, %inst27
>     %inst34 = mul i32 %inst33, %inst32
>     %inst35 = add nuw nsw i64 poison, 1
>     %inst36 = getelementptr inbounds i32, ptr addrspace(1) poison, i64 %inst35
>     %inst37 = load i32, ptr addrspace(1) %inst36, align 4
>     %inst38 = add i32 %inst37, -1
>     store i32 %inst38, ptr addrspace(1) %inst36, align 4
>     %inst39 = mul i32 %inst38, 47961
>     %inst40 = add i32 %inst39, -1
>     %inst41 = mul i32 %inst38, %inst34
>     %inst42 = mul i32 %inst41, %inst40
>     %inst43 = add nuw nsw i64 %inst35, 1
>     %inst44 = getelementptr inbounds i32, ptr addrspace(1) poison, i64 %inst43
>     %inst45 = load i32, ptr addrspace(1) %inst44, align 4
>     %inst46 = add i32 %inst45, -1
>     store i32 %inst46, ptr addrspace(1) %inst44, align 4
>     %inst47 = mul i32 %inst46, 47961
>     %inst48 = add i32 %inst47, -1
>     %inst49 = mul i32 %inst46, %inst42
>     %inst50 = mul i32 %inst49, %inst48
>     %inst51 = add nuw nsw i64 %inst43, 1
>     %inst52 = getelementptr inbounds i32, ptr addrspace(1) poison, i64 %inst51
>     %inst53 = load i32, ptr addrspace(1) %inst52, align 4
>     %inst54 = add i32 %inst53, -1
>     store i32 %inst54, ptr addrspace(1) %inst52, align 4
>     %inst55 = mul i32 %inst54, 47961
>     %inst56 = add i32 %inst55, -1
>     %inst57 = mul i32 %inst54, %inst50
>     %inst58 = mul i32 %inst57, %inst56
>     br label %bb1
>   }
>   
>   attributes #0 = { "target-features"="+avx" }
>
> Command:
>
>   opt -passes=slp-vectorizer -disable-output ir.ll
>
> Result:
>
>   opt: llvm-project/llvm/include/llvm/ADT/DenseMap.h:1251: llvm::DenseMapIterator<KeyT, ValueT, KeyInfoT, Bucket, IsConst>::value_type* llvm::DenseMapIterator<KeyT, ValueT, KeyInfoT, Bucket, IsConst>::operator->() const [with KeyT = llvm::Value*; ValueT = llvm::SmallVector<llvm::Instruction*>; KeyInfoT = llvm::DenseMapInfo<llvm::Value*, void>; Bucket = llvm::detail::DenseMapPair<llvm::Value*, llvm::SmallVector<llvm::Instruction*> >; bool IsConst = false; llvm::DenseMapIterator<KeyT, ValueT, KeyInfoT, Bucket, IsConst>::pointer = llvm::detail::DenseMapPair<llvm::Value*, llvm::SmallVector<llvm::Instruction*> >*; llvm::DenseMapIterator<KeyT, ValueT, KeyInfoT, Bucket, IsConst>::value_type = llvm::detail::DenseMapPair<llvm::Value*, llvm::SmallVector<llvm::Instruction*> >]: Assertion `Ptr != End && "dereferencing end() iterator"' failed.
>   PLEASE submit a bug report to https://github.com/llvm/llvm-project/issues/ and include the crash backtrace.
>   Stack dump:
>   0.      Program arguments: bin/opt -passes=slp-vectorizer -disable-output bugpoint-reduced-simplified-minimized.ll
>    #0 0x0000000003ab5864 llvm::sys::PrintStackTrace(llvm::raw_ostream&, int) llvm-project/llvm/lib/Support/Unix/Signals.inc:565:0
>    #1 0x0000000003ab5c53 PrintStackTraceSignalHandler(void*) llvm-project/llvm/lib/Support/Unix/Signals.inc:639:0
>    #2 0x0000000003ab3783 llvm::sys::RunSignalHandlers() llvm-project/llvm/lib/Support/Signals.cpp:104:0
>    #3 0x0000000003ab529f SignalHandler(int) llvm-project/llvm/lib/Support/Unix/Signals.inc:410:0
>    #4 0x00007f1bd34035e0 __restore_rt sigaction.c:0:0
>    #5 0x00007f1bd1f691f7 raise (/lib64/libc.so.6+0x351f7)
>    #6 0x00007f1bd1f6a8e8 abort (/lib64/libc.so.6+0x368e8)
>    #7 0x00007f1bd1f62266 __assert_fail_base (/lib64/libc.so.6+0x2e266)
>    #8 0x00007f1bd1f62312 (/lib64/libc.so.6+0x2e312)
>    #9 0x0000000003dd059a llvm::DenseMapIterator<llvm::Value*, llvm::SmallVector<llvm::Instruction*, 6u>, llvm::DenseMapInfo<llvm::Value*, void>, llvm::detail::DenseMapPair<llvm::Value*, llvm::SmallVector<llvm::Instruction*, 6u>>, false>::operator->() const llvm-project/llvm/include/llvm/ADT/DenseMap.h:1252:0
>   #10 0x0000000003d87336 (anonymous namespace)::HorizontalReduction::tryToReduce(llvm::slpvectorizer::BoUpSLP&, llvm::TargetTransformInfo*, llvm::TargetLibraryInfo const&) llvm-project/llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp:13046:0
>   #11 0x0000000003d8a956 llvm::SLPVectorizerPass::vectorizeHorReduction(llvm::PHINode*, llvm::Value*, llvm::BasicBlock*, llvm::slpvectorizer::BoUpSLP&, llvm::TargetTransformInfo*, llvm::SmallVectorImpl<llvm::WeakTrackingVH>&)::'lambda'(llvm::Instruction*, llvm::Value*&, llvm::Value*&)::operator()(llvm::Instruction*, llvm::Value*&, llvm::Value*&) const llvm-project/llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp:13745:0
>   #12 0x0000000003d8abcb llvm::SLPVectorizerPass::vectorizeHorReduction(llvm::PHINode*, llvm::Value*, llvm::BasicBlock*, llvm::slpvectorizer::BoUpSLP&, llvm::TargetTransformInfo*, llvm::SmallVectorImpl<llvm::WeakTrackingVH>&) llvm-project/llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp:13760:0
>   #13 0x0000000003d8af43 llvm::SLPVectorizerPass::vectorizeRootInstruction(llvm::PHINode*, llvm::Value*, llvm::BasicBlock*, llvm::slpvectorizer::BoUpSLP&, llvm::TargetTransformInfo*) llvm-project/llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp:13812:0
>   #14 0x0000000003d8d040 llvm::SLPVectorizerPass::vectorizeChainsInBlock(llvm::BasicBlock*, llvm::slpvectorizer::BoUpSLP&) llvm-project/llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp:14254:0
>   #15 0x0000000003d7ef19 llvm::SLPVectorizerPass::runImpl(llvm::Function&, llvm::ScalarEvolution*, llvm::TargetTransformInfo*, llvm::TargetLibraryInfo*, llvm::AAResults*, llvm::LoopInfo*, llvm::DominatorTree*, llvm::AssumptionCache*, llvm::DemandedBits*, llvm::OptimizationRemarkEmitter*) llvm-project/llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp:11703:0
>   #16 0x0000000003d7ea2f llvm::SLPVectorizerPass::run(llvm::Function&, llvm::AnalysisManager<llvm::Function>&) llvm-project/llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp:11634:0
>   #17 0x0000000003f47c92 llvm::detail::PassModel<llvm::Function, llvm::SLPVectorizerPass, llvm::PreservedAnalyses, llvm::AnalysisManager<llvm::Function>>::run(llvm::Function&, llvm::AnalysisManager<llvm::Function>&) llvm-project/llvm/include/llvm/IR/PassManagerInternal.h:90:0
>   #18 0x000000000312d1bc llvm::PassManager<llvm::Function, llvm::AnalysisManager<llvm::Function>>::run(llvm::Function&, llvm::AnalysisManager<llvm::Function>&) llvm-project/llvm/include/llvm/IR/PassManager.h:521:0
>   #19 0x0000000003f506ce llvm::detail::PassModel<llvm::Function, llvm::PassManager<llvm::Function, llvm::AnalysisManager<llvm::Function>>, llvm::PreservedAnalyses, llvm::AnalysisManager<llvm::Function>>::run(llvm::Function&, llvm::AnalysisManager<llvm::Function>&) llvm-project/llvm/include/llvm/IR/PassManagerInternal.h:90:0
>   #20 0x000000000312cb92 llvm::ModuleToFunctionPassAdaptor::run(llvm::Module&, llvm::AnalysisManager<llvm::Module>&) llvm-project/llvm/lib/IR/PassManager.cpp:125:0
>   #21 0x0000000003f50632 llvm::detail::PassModel<llvm::Module, llvm::ModuleToFunctionPassAdaptor, llvm::PreservedAnalyses, llvm::AnalysisManager<llvm::Module>>::run(llvm::Module&, llvm::AnalysisManager<llvm::Module>&) llvm-project/llvm/include/llvm/IR/PassManagerInternal.h:90:0
>   #22 0x000000000312cecc llvm::PassManager<llvm::Module, llvm::AnalysisManager<llvm::Module>>::run(llvm::Module&, llvm::AnalysisManager<llvm::Module>&) llvm-project/llvm/include/llvm/IR/PassManager.h:521:0
>   #23 0x0000000001bf4eeb llvm::runPassPipeline(llvm::StringRef, llvm::Module&, llvm::TargetMachine*, llvm::TargetLibraryInfoImpl*, llvm::ToolOutputFile*, llvm::ToolOutputFile*, llvm::ToolOutputFile*, llvm::StringRef, llvm::ArrayRef<llvm::PassPlugin>, llvm::opt_tool::OutputKind, llvm::opt_tool::VerifierKind, bool, bool, bool, bool, bool, bool) llvm-project/llvm/tools/opt/NewPMDriver.cpp:522:0
>   #24 0x0000000001c1f4f2 main llvm-project/llvm/tools/opt/opt.cpp:719:0
>   #25 0x00007f1bd1f55c05 __libc_start_main (/lib64/libc.so.6+0x21c05)
>   #26 0x0000000001bed2a9 _start (llvm-project/buildDA/bin/opt+0x1bed2a9)
>
> It doesn't crash if I revert 26fec4e845a833214d2b0036ea90f1b1c2418d50 <https://reviews.llvm.org/rG26fec4e845a833214d2b0036ea90f1b1c2418d50> and 5dccea5a68fb5181ab88ce6faac4668934f35cd7 <https://reviews.llvm.org/rG5dccea5a68fb5181ab88ce6faac4668934f35cd7>.

Thanks for the report, the crash reason is different. As I understand, the patch did not cause the crash but revealed the existing one. Will fix it ASAP.

Repository:
  rG LLVM Github Monorepo

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  https://reviews.llvm.org/D140580/new/

https://reviews.llvm.org/D140580